[Characteristics and Reactivity of VOCs in a Typical Industrial City in Summer].

To investigate the ambient pollution caused by volatile organic compounds (VOCs) in a typical industrial city in summer, the characteristics and chemical reactivity from VOCs and the causes of ozone (O) pollution were analyzed using online VOCs measurements during polluted and non-polluted periods in Zibo city in July 2020. The results showed that the average hourly concentration of total volatile organic compounds (TVOC) during the polluted period[(50.6±28.3)] μg·m was 32.5% higher than that during the non-polluted period[(38.2±24.9) μg·m]. The contribution of all VOCs categories were as follows:alkanes>aromatics>alkenes>alkynes, and the diurnal averages of TVOC and O concentrations were opposite during the polluted and non-polluted period. Ozone formation potential (OFP),·OH radical loss rate (), and secondary organic aerosol formation potential (SOA) during the polluted period were higher than those during the non-polluted period. Alkenes contributed most to OFP and , whereas aromatics contributed most to SOA. The tendency of the diurnal average of OFP and SOA was overall consistent with that of TVOC. The priority species of OFP, , and SOA were alkenes and aromatics. The VOCs/NO method was applied to identify the O-VOC-NO sensitivity during the polluted and non-polluted periods, and the results showed that the photochemical regimes were VOCs-limited and transition regions. In addition, the smog production model (SPM) was employed to identify the O formation regime, and the results showed that those during the polluted period were identified as VOCs-limited and transition regions from 08:00 to 16:00, whereas the non-polluted period was mainly considered to be VOCs-limited. To mitigate the O pollution in summertime, the synergistic control of VOCs (especially alkenes and aromatics) and NO emissions should be enforced.